T-cell mediated diseases represent a large number of immune system disorders. In particular, T-cells are thought to be the cells that start and perpetuate autoimmune diseases. Autoimmune diseases are a group of eighty serious, chronic illnesses that afflict millions of people in the United States alone. Autoimmune diseases are characterized by reactivity of the immune system to endogenous (self) antigens. These immune responses to self antigens are maintained by the persistent or recurrent activation of self-reactive T-cells and, directly or indirectly, the self-reactive T-cells are responsible for the characteristic tissue injury and destruction seen in autoimmune diseases. Although many treatments for autoimmune diseases and other T-cell mediated diseases have been proposed, there is still a need for additional treatments.